with GPu getting bigger and bigger, high wattage SFX psu being extremely expensive and cpu getting hotter and hotter, this seems to be a great choice for high performance SFF built. However I think 20L is a bit too big and the case can be a bit smaller. There is SFF case call the Jimu D+ D (its started as a FromD T1 clone but later revision seems to became its own thing) that can fit almost the same hardware, with the exception on worst GPU compatibilities at 328mm 4 slots and 280 rad max, at a way smaller 14.8L volumn.
I'm not saying the case should be that small, in fact one of the draw back of that case is that 328mm seems to be too small for most 4090 on the market today, and the case being extremely expensive don't helps either. But I think this case could be a bit smaller (say about 18L) without loose too much of the current hardware compatibilities.
But Overall I am very exited for this case, its great to see better space efficient case design in the mainstream market.